A window through the walls of our classroom. This is an interactive learning ecology for students and parents in my Pre-Cal Math 40S class. This ongoing dialogue is as rich as YOU make it. Visit often and post your comments freely.

Sunday, September 23, 2007

circular functions

hi its Anthony. Sorry i started this so late, i was at work for the last few days. Anywho we started off the class doing some warm up graphing questions. later in the class Mr. K started something new. Writing equations for graphs. He started off by showing the relationship between cos(x) and sin(x). Turns out both of these graphs are the same, only difference is the horizontal shift. What i mean by that is:

cos (x) = sin(x+π/2)andsin(x) = cos(x-π/2)

Now moving on. Graphing graphs from equations is easy but writing equations from graphs was something new to most of us on friday. Remember when writing equations for graphs use DABC. What i mean by DABC is find the verticle shift, amplitude, period, and the horizontal shift. Also Mr. K can never stress enough that i quote " B IS NOT THE PERIOD... B IS NOT NOT NOT NOT NOT THE PEIORD." B helps determin the period. with the following equation:

period = 2π/B

Another new thing we learned was how to graph tan(x).

the dotted lines are the asymptotes (where the graph will never touch). the reason they will never touch is because on the unit circle at those specific points because tan is parallel with the y axis. lastly graphing trig functions should be in yourmath dictionarys.The next scribe is